1. Field of the Invention
This invention relates to a map represented by, for example, a printing method for people to visually recognize the content thereof immediately with the naked eye, the map being formed so that the content of the indications of a road or the like which contain graphic representations, symbols, letters the like, and the position thereof can be coded and recorded, and further to a method for coding such map representations.
2. Description of Related Art
As a map which is carried during driving a vehicle or during a trip, conventionally, a map display unit which is capable of displaying a map on its display screen such as a LCD panel have been well known as well as a printed map of a variety of scales.
Particularly, a car navigation system which has been recently mounted on vehicles, displays a map on the LCD screen so as to allow people to grasp the displayed map with the same visual sensitivity as when they see a printed map (hereinafter referred to analog map). The data indicating the content of a map which is coded by digital values and is memorized in a storage device is read and, for example, the map of a subject area is displayed on the aforementioned screen substantially in the same manner as in the printed map so that people can see the displayed map according to the same visual sensitivity as when they see the analog map. In order to display the information about on what point on the displayed map and in which direction a vehicle incorporating this navigation system is travelling, the position of the aforementioned vehicle is detected by means of an artificial satellite, beacon or the like and displayed on the map displayed on the aforementioned screen.
However, it is not easy to produce the data necessary for digitizing the data of the analog map. Additionally, because a large amount of information represented according to different scales are required for a map of even the same area, depending on the purpose of use of the map, the amount of data necessary for the digitized map is very huge. Thus, it takes quite complicated steps to read a subject map data from various map data stored in the storage device and then display the map data of a desired scale of a desired area on the display screen.
Accordingly, if it is possible to specify an area which is desired to be displayed, immediately, according to the analog map, a location or a place which is desired to be displayed can be displayed on the display screen of the car navigation system without any complicated procedure. Thus, such system is considered to be very useful. If a method in which an analog map is recorded as map data more easily than in conventional methods can be realized, the versatility of the system is enhanced in addition to ease of the display operation.